JP2002118037A - Electric double-layer capacitor pack - Google Patents

Abstract

(57) [Problem] To provide an electric double layer capacitor pack with high long-term charge / discharge reliability. SOLUTION: In an electric double layer capacitor pack in which a plurality of unit electric double layer capacitors in which one or more pairs of a positive electrode and a negative electrode are stacked via a separator are connected, the direction of the electrodes of the unit electric double layer capacitors is perpendicular to the stacking direction. A plurality of unit electric double-layer capacitors connected by positive and negative conductive connection leads taken out in different directions are arranged on the same plane, and the entire unit electric double-layer capacitor is covered on both sides by a flexible exterior material. An electric double layer capacitor pack in which the periphery of the double layer capacitor is sealed and the space between each unit electric double layer capacitor is sealed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electric double layer capacitor pack in which a plurality of electric double layer capacitors are conductively connected, and more particularly to an electric double layer capacitor pack covered with a flexible outer material.

[0002]

2. Description of the Related Art An electric double layer capacitor is a capacitor utilizing an electric double layer capacitance formed at an interface between an electrode and an electrolytic solution, and has a feature that a much larger capacitance can be obtained as compared with other capacitors. Utilizing such characteristics, it has been used as a backup power supply for a memory of an electronic device. Further, development as a power storage means is being advanced utilizing the fact that a large capacitance can be obtained. In addition, since it does not involve a chemical reaction, it can be charged and discharged in a very short time in accordance with a time constant, and thus has attracted attention as a power source for electric vehicles and the like.

The withstand voltage of an electric double layer capacitor is limited by the electrolysis voltage of an electrolyte used. Water-based electrolytes are limited by the electrolysis voltage of water,
The maximum operating voltage is about 1 V, which is higher than that using a non-aqueous electrolytic solution even though it is higher than that using an aqueous electrolytic solution.
About V. As described above, since the rated voltage of the electric double layer capacitor is relatively low, any voltage of one electric double layer capacitor cannot efficiently operate any electronic circuit such as a switching converter. For this reason, it is indispensable to increase the rated voltage by connecting a large number of electric double-layer capacitors in series in order to store electric power or use as a power source for electric equipment such as a motor.

[0004] When used for a power source of an automobile or the like, it is important that the mass is small in addition to the electrical characteristics such as capacitance. Therefore, for such an application, an electric double layer capacitor using a flexible exterior material in which a synthetic resin film having a small mass is laminated with an aluminum foil or the like instead of using a metal can as an exterior material is preferable.

On the other hand, the electric double layer capacitor has a characteristic that the charging / discharging speed, that is, the flowing current can be increased as compared with the secondary battery, because the chemical change of the substance is not accompanied at the time of charging / discharging. However, in order to effectively utilize such characteristics, conductive connection leads to be attached to the electric double layer capacitor are required to have a small voltage drop and a small electric resistance even when a large current is applied. .

In order to reduce the electrical resistance of the conductive connection lead, it is necessary to increase the cross-sectional area of the conductive connection lead, and the band-shaped conductive connection lead used as the conductive connection lead of the electric double layer capacitor is required. At least one of the thickness and the width has been increased. However, in the case of an electric double layer capacitor sealed with a flexible sealing material, since the conductive connection leads are present in the sealing portion, the thick and wide conductive connection leads do not adversely affect the sealing characteristics. I couldn't.

In particular, in an electric double layer capacitor using a non-aqueous electrolyte, the sealing property is extremely important.
Infiltration of moisture in the air together with leakage of the electrolyte from the sealing portion leads to deterioration of the electric characteristics of the electric double layer capacitor, and the sealing characteristics are very closely related to the life of the electric double layer capacitor, It has been required to maintain good sealing properties for a long period of time.

[0008]

SUMMARY OF THE INVENTION The present invention relates to an electric double-layer capacitor pack in which a plurality of electric double-layer capacitors sealed with a flexible sealing material are connected to each other. It is an object of the present invention to provide an electric double layer capacitor pack capable of maintaining the following.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric double layer capacitor pack in which a plurality of unit electric double layer capacitors in which at least one set of a positive electrode and a negative electrode are laminated via a separator are connected. A plurality of unit electric double-layer capacitors connected at right angles to the lamination direction of the electrodes of the capacitor and connected by positive and negative conductive connection leads drawn in different directions are arranged on the same plane, and the whole is flexible. The problem can be solved by an electric double layer capacitor pack in which both sides are covered with the conductive exterior material and the periphery of the unit electric double layer capacitor is sealed, and the space between the unit electric double layer capacitors is sealed. Also, one continuous flexible exterior material is folded to cover the entire unit electric double layer capacitor from both sides, and the three sides except for the bent portion are sealed, and the space between each unit electric double layer capacitor is sealed. The electric double layer capacitor pack described above. Further, in the electric double layer capacitor pack, the unit electric double layer capacitors are arranged in a line. In addition, the electric double layer capacitor pack includes the unit electric double layer capacitors arranged in a square shape.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The electric double layer capacitor of the present invention uses a large cross-sectional area as a conductive connection lead by reducing the area of a portion of the flexible sealing material which comes into contact with the outside of the sealing portion. It has been found that even in an electric double layer capacitor, the risk of leakage from the sealing portion can be reduced.

The present invention will be described below with reference to the drawings.
FIG. 1 is a view for explaining an embodiment of an electric double layer capacitor pack of the present invention, which is an electric double layer capacitor pack composed of four unit electric double layer capacitors. FIG.
1A is a plan view, and FIG. 1B is a cross-sectional view taken along line AA ′. The electric double layer capacitor pack 1 has a plurality of unit electric double layer capacitors 2 arranged in a line on the same plane, and has polarities in directions perpendicular to the stacking direction of the electrodes constituting the electric double layer capacitor and different from each other. The different conductive connection leads 3 are taken out, and the conductive connection leads 3 between the unit electric double layer capacitors are connected in series. The entire unit electric double layer capacitor 2 is covered with a flexible sealing material 4 disposed on both sides, and surrounding first sealing portion 5, second sealing portion 6, third sealing portion 7, and fourth sealing portion 8 are provided. To form a seal with the outside air. Also, between the adjacent unit electric double layer capacitors, the portion of the conductive connection lead 3 connecting the unit electric double layer capacitors is sealed by the electric double layer capacitor interposing portion 9, and the space between the unit electric double layer capacitors is formed. It is divided,
The sealing portion that partitions between the unit electric double layer capacitors is a sealing portion that is not located between the unit and the outside air.

When n unit electric double layer capacitors having a square outer shape are arranged in series and sealed by the above-described method, the length of one side of the unit electric double layer capacitor is reduced. When one sealing unit is used, the sealing part located between the outside air and the outside air is (2n + 2) sealing units.

On the other hand, when flexible sealing materials are arranged on both sides of each of the n unit electric double layer capacitors and individually sealed, the sealing portion located between the outside air and the unit is 4n sealing units. Becomes Therefore, according to the method of the present invention, the sealing portion located between the outside air and (4n− (2n + 2)) =
(2n-2) The number of sealing units is reduced, and in the case where 20 unit electric double layer capacitors are connected in series, the number of sealing portions located between 38 units and the outside air decreases. In addition, since the sealing portion through which the conductive connection lead passes is only two places at both ends, the sealing portion through which the conductive connection lead having a large width and a large thickness passes decreases.
This will greatly contribute to improving the sealing properties.

Further, in the electric double layer capacitor pack of the present invention, as shown in FIG. 1, it is preferable to attach a voltage measuring terminal 10 to each unit electric double layer capacitor. The voltage measurement terminal 10 enables the voltage of each unit electric double layer capacitor to be detected, and when the charge / discharge control device is controlled based on the detected voltage, effective charge / discharge control becomes possible. In addition, it becomes easy to detect the deterioration of the electric characteristics of each electric double layer capacitor. For example, in an electric double layer capacitor pack in which a number of unit electric double layer capacitors are connected in series, if the electric characteristics vary,
Although it is necessary to adjust the entire voltage so that the voltage distributed to each unit electric double layer capacitor does not exceed the usable voltage, the voltage measurement terminal is also effective in such a case. Further, since the voltage measuring terminal 10 may have a sufficiently small cross-sectional area that does not substantially require the flow of an electric current, there is little possibility that the sealing terminal will have any effect on the sealing characteristics regardless of the portion provided. . Therefore, the position for taking out the voltage measuring terminal 10 may be connected to the conductive connection lead located inside each unit electric double layer capacitor, or may be connected to the conductive connection lead located between the unit electric double layer capacitors. Alternatively, it may be taken out at a sealing portion between adjacent unit electric double layer capacitors.

FIG. 2 is a plan view for explaining another embodiment of the electric double layer capacitor pack of the present invention.
In the electric double layer capacitor pack 1, a plurality of unit electric double layer capacitors 2 are arranged in a line on the same plane, and conductive connecting leads 3 having different polarities in a direction perpendicular to the lamination direction of the electrodes and opposite to each other. Then, each of the conductive connection leads is connected in series. The entire unit electric double layer capacitor 2 is covered on both sides by bending a continuous flexible sealing material 11, and the three sides excluding the bent portion 12 are sealed by a method such as heat fusion, and the first sealing portion 5 is sealed. , A second sealing portion 6, and a third sealing portion 7. Further, between each adjacent unit electric double layer capacitor,
The portion of the conductive connection lead 3 that couples the unit electric double layer capacitors is sealed to partition the unit electric double layer capacitors.

The sealing portions located between each electric double layer capacitor and the outside air have two sides of the first sealing portion 5 and the third sealing portion 7 at both ends and both ends regardless of the number connected in series. In the middle unit electric double layer capacitor except for (1), only one side facing the second sealing portion 6 is located between itself and the outside air. Therefore, in the electric double layer capacitor pack composed of n unit electric double layer capacitors according to the method described in FIG. 2, the sealing portion located between the outside air and the outside air is sealed at one side of the square unit electric double layer capacitor. When the length of the part is set to one sealing unit, the unit is (n + 2) sealing units, which is smaller than the case where one flexible exterior material is arranged on both sides of each unit electric double layer capacitor and sealing is performed. (4n− (n + 2)) = (3n−2) The number of sealing units is reduced. When 20 unit electric double layer capacitors are sealed as shown in FIG. 2, it is possible to reduce the number of the sealing portions between the outside air and the outside air in 58 sealing units. In the multilayer capacitor pack, it is possible to reduce the number of sealing portions located between more external air than that shown in FIG.

The electric double layer capacitor pack of the present invention as described above is used not only by spreading it in a plane but also by increasing the length of the conductive connection lead between the unit electric double layer capacitors. It may be used by bending. In addition, the electric double layer capacitor pack of the present invention is not limited to those arranged in a row in the horizontal direction, and those arranged in a row in the horizontal direction as described below are further combined and arranged in a quadrilateral shape. It may be.

FIG. 3 is a plan view for explaining another embodiment of the electric double layer capacitor pack of the present invention.
The electric double layer capacitor pack 1 has 16 unit electric double layer capacitors arranged in a square shape. In the end row, the unit electric double layer capacitor excluding one end has conductive connection leads 3 taken out in opposite directions, and one end has conductive connection leads taken out at right angles to each other. Conductive connection is made with the electric double layer capacitor, and in each row in the middle, the conductive connection leads are taken out at both ends in a direction perpendicular to each other. The conductive connection lead is taken out.

The whole of the unit electric double layer capacitor 2 is covered on both sides with a flexible sealing material 4, and the whole unit electric double layer capacitor 2 is sealed by a method such as heat sealing to form a peripheral unit. 1 sealing section 5, 2nd sealing section 6, 3rd sealing section 7
Only the fourth sealing portion 8 forms a sealing portion with the outside air, and the unit electric double layer capacitors are sealed and partitioned by the electric double layer capacitor interposing portion 9. When a voltage measurement terminal is provided, it is preferable to take out the voltage measurement terminal provided on the electric double layer capacitor in the intermediate portion so that the lead does not cross the conductive connection lead.

When n × n unit electric double layer capacitors are arranged in a square shape according to the method of the present invention, the sealing portion on one side of the square unit electric double layer capacitor is compared with a case where the individual electric double layer capacitors are individually sealed. (4n × n− (2n + 2 (n−1))) = (4n
(N-1) +2) The number of sealing portions in contact with the outside air in the sealing unit is reduced, and only two sealing portions contact the outside air through which the conductive connection leads pass. Furthermore, when one continuous flexible exterior material is used and the both sides of the unit electric double layer capacitor arranged on a plane are folded to be sealed, only three sides are in contact with the outside air. Therefore, the sealing portion that comes into contact with the outside air is (4m × m− (m + 2 (m−1))) =
(4 m ² -3 m + 2) The number of sealing units is reduced.

As described above, in the electric double layer capacitor pack of the present invention, the number of sealing portions between the capacitor and the outside air can be reduced, so that the sealing characteristics can be easily improved. Therefore, according to the present invention, a reliable sealing characteristic can be obtained even when a large conductive connection lead having a thickness of about 0.5 mm and a width of about 100 mm is used in response to the passage of a large current. It is possible to obtain an electric double layer capacitor pack which is capable of charging and discharging a large current, has a large withstand voltage, is lightweight and has high reliability.

The flexible exterior material used in the present invention includes:
A multi-layered flexible film including a non-permeable layer such as aluminum foil, an easily adhesive layer such as polyethylene, a protective layer such as polyester resin, and the like can be used. For example, a thermoplastic resin layer of polyethylene, polypropylene, ionomer, ethylene-methacrylate copolymer resin, ethylene- (meth) acrylate copolymer resin, etc. is bonded to the inner surface of the aluminum foil, that is, the surface on the unit electric double layer capacitor side, with an adhesive. Lamination is carried out by heat sealing without a layer or using an adhesive layer, and on the opposite side is laminated a polyester resin such as polyethylene terephthalate or a nylon resin.

Further, in order to improve the heat-sealing property of the inner surface such as polyethylene or polypropylene, an unstretched polyethylene film having a good sealing property may be used for the inner surface film. On the sealing surface, a maleic acid-modified olefin resin layer may be formed. Furthermore, a portion of the sealing portion where the conductive connection lead and the exterior material come into contact with each other is preliminarily coated with a maleic olefin or the like to perform surface treatment, or the conductive connection lead is covered with a maleic olefin film or the like to form a joint with the exterior material. May be enhanced. Further, an unstretched polyethylene film or the like having good heat-sealing properties may be disposed in a portion where there is no conductive connection lead so that no step is formed between a portion where the conductive connection lead does not exist and a portion where the conductive connection lead does not exist.

[0024]

As described above, in the electric double layer capacitor pack in which a plurality of unit electric double layer capacitors are conductively connected and sealed with a flexible outer material, the number of sealing portions between the unit and the outside air can be reduced. It is possible to provide a light-weight electric double-layer capacitor pack that has good characteristics and can be expected to operate reliably over a long period of time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of an electric double layer capacitor pack according to the present invention.

FIG. 2 is a diagram illustrating another embodiment of the electric double layer capacitor pack of the present invention.

FIG. 3 is a view for explaining another embodiment of the electric double layer capacitor pack of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electric double layer capacitor pack, 2 ... Unit electric double layer capacitor, 3 ... Conductive connection lead, 4 ... Flexible sealing material,
5 1st sealing part 2 2nd sealing part 3 3rd sealing part 8
... Fourth sealing part, 9 ... Electric double layer capacitor gap part,
0: terminal for voltage measurement, 11: continuous flexible sealing material, 1
2 ... Bend

Claims (2)

[Claims] 1. An electric double layer capacitor pack in which a plurality of unit electric double layer capacitors in which at least one set of a positive electrode and a negative electrode are stacked via a separator are connected, a direction perpendicular to the direction of lamination of the electrodes of the unit electric double layer capacitors. A plurality of unit electric double layer capacitors connected by positive and negative conductive connection leads which are taken out in different directions are arranged on the same plane, and the entire unit is covered on both sides by a flexible exterior material. An electric double layer capacitor pack, wherein the periphery of the electric double layer capacitor is sealed and the space between each unit electric double layer capacitor is sealed. 2. A single continuous flexible exterior material is folded to cover the entire unit electric double layer capacitor from both sides,
2. The electric double layer capacitor pack according to claim 1, wherein the three sides except for the bent portion are sealed, and the space between the unit electric double layer capacitors is sealed.